The present invention relates to a product conveying unit.
More specifically, the present invention relates to a unit for conveying substantially elongated products, to which the following description refers purely by way of example.
Though specific reference is made in the following description to a unit for conveying diapers, the same also applies to other substantially elongated products, such as food products.
On diaper manufacturing systems, a succession of U-folded diapers is fed to a stacking device along a given path, along which each diaper is fed parallel to its longitudinal axis, with the U-folded edge facing forwards and crosswise to the longitudinal axis, and is maintained in this position up to the stacking device.
Known stacking devices normally comprise a pocket conveyor, the pockets of which are fed in steps across the path of the diapers, in a direction crosswise to both the traveling direction and the folded edge of the diapers, and are arrested successively along the path of the diapers to enable each diaper to be inserted, folded edge first, inside a respective pocket.
In addition, obviously, to depending on the traveling speed of the diapers, the operating frequency of the stacking device also depends, for a given traveling speed, on the length of the diapers, i.e. the dimension of the diapers crosswise to the folded edge, and which is always greater than the dimension parallel to the folded edge. That is, the longer the diaper is, the longer it takes, at a given traveling speed, for each to be inserted inside the respective pocket on the stacking device, and the slower the operating frequency of the stacking device is.
On the other hand, the operating frequency of the stacking device can only be increased so far by increasing the traveling speed of the diapers. Experience has shown, in fact, that, despite the folded edge being the strongest part of the diaper, the diapers are invariably damaged on impact with the bottom of the respective pockets, when the traveling speed of the diapers--which corresponds to a given output speed of the system and a given operating frequency of the stacking device--is increased over and above a given limit.